Date of Award

Summer 2021

Document Type

Open Access Thesis


Epidemiology and Biostatistics

First Advisor

Susan Steck


Background- Although ovarian cancer is a rare disease, it is the 5th leading cause of cancer-related deaths among women in the United States. Diabetes is a serious chronic disease that plagues over 436 million adults worldwide and was ranked 7th in causes of death in the US in 2017. Epidemiologic evidence suggests that diabetes may lead to an increased risk of ovarian cancer due to shared risk factors such as sedentary behaviors, smoking and poor diet or through biological mechanisms related to hyperglycemia and obesity, but the epidemiologic evidence yields mixed results. Certain anti-diabetic medications may increase the risk of ovarian cancer, while others can significantly decrease the risk of ovarian cancer. The present study examines diabetes, anti-diabetic medication use, and the risk of ovarian cancer in the PLCO Cancer Screening Trial. Methods- Cox proportional hazards regression was used to calculate HRs and 95% CIs for ovarian cancer for individuals with diabetes versus those without using a simple model adjusted for age and study arm, a multivariable model, models stratified by race, and in sensitivity analyses, models stratified by study arm and restricting to participants with non-missing data for key covariates. Results-A slight inverse relationship between diabetes and ovarian cancer risk was observed though the 95% CI included the null. Among PLCO intervention arm participants, a stronger inverse association was observed while there was no association among control arm participants. Among non-Hispanic Black participants, the results suggested an increased risk of ovarian cancer among diabetics compared to non-diabetics. Given the small number of ovarian cancer cases who completed the medication use questionnaire, only descriptive statistics were able to be reported for anti-diabetic medication use. Conclusion- Our results suggest a possible inverse relationship between diabetes and the risk of ovarian cancer overall and particularly among women in the PLCO screening intervention arm. The opposing actions of diabetes and anti-diabetic medication usage on the risk of ovarian cancer warrant further research on this topic. Studies that obtain detailed information on diabetes severity, duration, and anti-diabetic medication usage are needed to clarify the associations with ovarian cancer risk.

Available for download on Tuesday, August 15, 2023

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